Les locales sont générées dans le dossier /usr/lib/locale

Lors de l'installation d'un paquetage, les messages d'avertissement suivant apparaissent:

perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = (unset),
        LC_ALL = (unset),
        LANG = "fr_FR.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory

Modifier le fichier /etc/locale.gen décommenter au minima en_US.UTF-8 UTF-8 et les locales

Relancer la génération des locales:

sudo /usr/sbin/locale-gen
 
# si locale-gen n'est pas disponible:
sudo localedef -i en_US -f UTF-8 en_US.UTF-8

sudo dpkg-reconfigure locales

• https://www.cyberciti.biz/faq/perl-warning-setting-locale-failed-in-debian-ubuntu/